Transportation orders fell 4.7 percent in September as civilian aircraft orders plummeted 41.6 percent, the Commerce Department (search) said. But even stripping out the drop in demand for long-lasting transportation goods, new orders fell 1 percent.

The report was much weaker than expected on Wall Street (search). Economists had forecast orders for durable goods, big-ticket items meant to last three years or more, to fall just 1.1 percent and had looked for orders to rise 0.8 percent outside transportation.

The report also showed a 1.2 percent decline in orders for non-defense capital goods, excluding aircraft, which economists look to as a proxy for future business spending.

The drop in demand for long-lasting manufactured goods was likely to renew concerns that soaring energy prices could be weighing on the economy. Upward revisions to August orders, however, could temper those concerns.

The Commerce Department said shipments of durable goods last month edged up just 0.1 percent. That figure was weaker than some economists had expected and could lead forecasters to reduce projections for third-quarter growth.

Wall Street economists had forecast U.S. gross domestic product to expand at a 3.6 percent annual rate in the July-September period. The Commerce Department is set to release its first snapshot of third-quarter growth on Friday.

The weakness in orders last month was fairly broad-based, with demand for computers and electronic products off 3.6 percent, electrical equipment orders down 3.5 percent and fabricated metal products 1.2 percent lower.

One bright spot was motor vehicle orders, which rose a robust 4.7 percent, the largest one-month increase since December 2004.